Help AT750/AT520 Diagnosis Sheet Return to Help Index

AT750 / AT520 Diagnosis Sheet

Machine has worked in the past, but stopped working. BOTH LATHE AND MILL DO NOT HAVE ANY POWER.
  This can be either 1 of 2 things.

Either there are loose wires between the Forward/reverse switch or the motor(s) has failed.

The way to determine the problem is to check all of the electrical wires from the forward/reverse switches to the motors.

If there was some loose wire(s) then tightening them should solve the problem.

If all the wires are connected properly, you can test the forward/reverse switch by swapping them, if either the lathe or mill motor switch combination is working. It is very rare that both the lathe and mill malfunction simultaneously.
Motor (lathe or mill motor) will not spin, only hum.
  Check all motor and switch connections to make sure there are no loose wires.

The problem could be the start capacitor. The way to test it is to turn on the machine andtry to give the chuck a little push. If it starts after the push, then you have determined it is the start capacitor. If it does not, then most likely the motor needs to be replaced.
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